Please Help me to fix the bug

Test 1: authData.php Auth exception: Refresh token has expired Exception: curl_close(): 57 is not a valid cURL handle resource SDK HTTP Error at _https://platform.devtest.ringcentral.com/restapi/oauth/token Response text: Previous: curl_close(): 57 is not a valid cURL handle resource #0 phar:///home/tamilwjv/public_html/demo/ring/ringapi/ringcentral.phar/ringcentral/ringcentral-php/src/Platform/Platform.php(214): RingCentralSDKHttpClient->send(Object(RingCentralPsr7Request)) #1 phar:///home/tamilwjv/public_html/demo/ring/ringapi/ringcentral.phar/ringcentral/ringcentral-php/src/Platform/Platform.php(301): RingCentralSDKPlatformPlatform->sendRequest(Object(RingCentralPsr7Request), Array) #2 phar:///home/tamilwjv/public_html/demo/ring/ringapi/ringcentral.phar/ringcentral/ringcentral-php/src/Platform/Platform.php(123): RingCentralSDKPlatformPlatform->requestToken('/restapi/oauth/...', Array) #3 /home/tamilwjv/public_html/demo/ring/ringapi/demo/authData.php(43): RingCentralSDKPlatformPlatform-